1. Field of the Invention
The present invention relates to an image forming apparatus, and to an image forming method employing a fusing process in view of energy-efficient use in response to print attribution information of to-be-formed images.
2. Description of the Background Art
Image forming apparatuses using electrophotography have been used as various machines such as copiers, laser printers, multi-functional apparatuses known as multi-functional peripherals (MFP), production printing machines, or the like. Colored micro-particles such as toner particles are used as a development agent for the electrophotography, and the toner is fused and fixed on a sheet of recording media such as a sheet of paper by applying heat and pressure, by which durable printed products can be produced.
In the electrophotography process, a fusing member is heated by a fusing heater to obtain a temperature required for a heat-applying fusing process, in which the fusing heater needs more electric power for the fusing process. In view of the desirability of energy savings and/or lower carbon emissions, it is preferable to reduce electric power consumption of the fusing heater. The amount of electric power required for the heat-applying fusing process using toner is mainly determined by the fusing temperature, and the fusing temperature in turn is determined by such factors such as the type of sheets, heat property of toner, or the like. Therefore, electric power consumption can be reduced by decreasing the fusing temperature.
Fusing technologies for electrophotography have been developed. For example, JP-2006-260185-A discloses a method of predicting a time for an image drawing process executed by an image analyzing unit based on the print contents and adjusting the timing of the issuance of an engine activation command for fusing.
In the method disclosed in JP-2006-260185-A, an activation command is issued to the print engine, but a time to start a printing operation is delayed when the image processing step takes a longer time. In such a situation, the print engine may be instructed not to return to the energy saving mode. With such a configuration, the activated print engine may not be set to the deactivated condition, by which electric power consumption can be reduced because an unnecessary power-down condition can be prevented. Further, in the method disclosed JP-2003-15461-A, to save energy, the fusing temperature is varied depending on the toner used for printing.
However, JP-2006-260185-A is focused on the activation timing of print engine and does not consider a process control in view of toner properties, contents of to-be-printed image, or the like. As a result, energy saving setting in view of to-be-formed images and/or the types of sheet may not be conducted.
Further, in JP-2003-15461-A, when the image forming apparatus returns from the energy saving mode to the print mode in which a printing operation can be conducted, the fusing temperature may be increased to a temperature required for full-color printing using all color toners. When monochrome printing is conducted using such image forming apparatus, the monochrome printing may be conducted using a higher fusing temperature, which may be too high for the monochrome printing.
As such, in the conventional art, when the image forming apparatus returns from the energy saving mode to the print mode, the fusing temperature may be increased to a too-high temperature for some image forming operations normally conducted in offices and/or homes.